Starch, and particularly modified starch, is used in foods to contribute to physical properties, such as, texture, viscosity, gel formation, adhesion, binding, moisture retention, film formation and homogeneity. However, it is undesirable for starch to affect the taste, odor, or color of the foods in which it is used.
The starch base, the milling process, and the type of chemical modification of the starch can all affect the sensory qualities of starch, for example, by imparting an unwanted flavor, odor, or color, or by masking the typical flavor of the food. Cereal-based starches, such as corn starch and wheat starch, are sometimes considered to have off-notes described as “cardboard- or cereal-like.” Root and tuber starches, such as tapioca and potato starch, are usually judged to be cleaner in flavor, but retain flavors characteristic of the starch and mask the flavor of the food. Residual protein and lipid that are not entirely extracted during the milling process can influence starch flavor.
Modification of the starch base can also affect flavor, impart unsuitable odors, and darken the color of the starch through the retention of residual components from the modification processing. Suspected components include hexanal, 2-heptanone, heptanal, trimethylbenzene, nonanal, BHT-aldehyde, and acetic acid.
Accordingly, there is an ongoing need for a method of purifying starches, especially food starches, to remove those components that cause unwanted tastes, odors and colors.